1. Field of the Invention
This invention relates to a speaker device, and more particularly to a speaker device which is small in size and has an excellent in low-frequency sound reproduction ability.
2. Description of Related Art
Examples of a low-frequency sound speaker (also called “bass speaker”) device for reproducing sound of low-frequency band with relatively flat frequency characteristic are disclosed in Japanese Patent Applications Laid-Open under Nos. 5-41896, 6-38290 and 2001-16673. However, in a speaker device having a port (“Bass Reflex type” and “Kelton type”), since the port is short and its pipe resonant frequency is high, the pipe resonant frequency of the port is remote from the Helmholtz resonant frequency caused by the mass of air in the port and the compliance in a cabinet. Therefore, when the pipe resonance is positively used, it is difficult to practically obtain low-frequency sound reproduction by combining those two resonances.